Method of refrigerating an article by contact with a vaporizable refrigerant



R. H. HILL 2,447,249 METHOD OF REFRIGERATING AN ARTICLE BY CONTACT WITHA VAPORIZABLB REFRIGERANT Filed Oct. 13, 1944 2 Sheets-Sheet J.

Aug. 17,

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R. H. HILL 2,447,2 METHOD OF REFRIGERATING AN ARTICLE BY CONTACT WITH AVAPORIZABLE REFRIGERANT Filed Oct. 13, 1944 2 Sheets-Sheet 2 F0 I a qIIII IF I 1 E :1 l o '1 Melt Or i- Q Q $0581"! .5. JIZ Z Z Patented Aug.17, 1948 METHOD OF REFRIGERATING AN ARTICLE BY CONTACT WITH AVAPORIZABLE RE- FRIGERANT Robert H. Hill, Elgin, Ill., assignor to TheMarison Company, Elgin, 111., a corporation of Illinois ApplicationOctober 13, 1944, Serial No. 558,566

2 Claims. 1

This invention relates to a method of and an' apparatus forrefrigeration.

In the art of refrigeration several methods of frigerating articles, theapparatus including producing the desired low temperature in thearticles have been used. One common method ofrefrigeration entails theuse of water ice and where a temperature below the freezing point ofwater is required, a salt is mixed with the water ice to attain therequired low temperatures. Another method entails the use of solidifiedcarbon dioxide 'gas and placing the such Dry Ice in contact with oradjacent to the article to be refrigerated. A third method involves theuse of sealed containers of frozen brine, commonly known as cold cans,the containers being likewise placed in contact with or adjacent to thearticle. A fourth method comprises extracting heat from the article bymechanical means operating in the vicinity of the article.

The above-mentioned refrigerating methods are subject to certainlimitations, particularlyv when the problem is to refrigerate articlesin transit. While water ice is nearly ideal for relatively higherrefrigerating temperatures, e. g. above 40 F., it is not satisfactoryfor lower temperatures since salt must beadded to lower the meltingpoint of the ice and this involves additional expense. In adddition, thebrine which results is quite corrosive to the vehicle structure and inthe case of railroads, to the various switches and controls along theright-of-way. Dry Ice eliminates the corrosive features of brine, but itis quite expensive and furthermore is. not readily controllable as tothe temperature produced. Cold cans-are not as expensive as Dry Ice, but

they must be returned for refreezing, which in volves handling andhauling unfrozen cans perhaps for considerable distances. Mechanicalrefrigeration, though satisfactory from the standpoint of creating andholding a desired tempera-.

means for effecting relative movement between a quantity of refrigerantand the articles to be refrigerated.

In general, this invention comprises utilizing liquid air as therefrigerant, a supply of the liquid air being placed in a receptacle ina chamber and then either movin the articles through the chamber incontact with the liquid air, or regulating the flow of liquid air intothe chamber, the temperature being varied by altering the quantity ofthe liquid air'used and the time during which the articles are exposedto it. There are three forms of the method by which this invention maybe carried out. In the first, the liquid air is placed in a receptaclein an enclosed chambar near the top thereof and the articles to berefrigerated are placed upon the floor or elsewhere near the bottom ofthe chamber.- The most useful in refrigerating vehicles, rooms orwarehouses. A thermostatic control may be in corporated in the sprayingdevice to maintain an even temperature.

In the second form, the articles to be refrigerated are mounted upon aconveyor, rack or the like andare inserted into a chamber beneath aspray of liquid air emanating from a perforated ture, createsmaintenance problems b'oth in-the form of periodic servicing andbreakdowns en route.

The principal object of this invention is to provide a method ofrefrigerating articles which is free from most of the limitations of themethods outlined above. More specifically, the object of this inventionis to provide'a refrigerating method container placed over the conveyor.This form is useful for quick-freezing the articles, that: is, forfrozen foods'and the like which must be frozen quickly and thentransported in a frozen state. When a conveyor is used, the temperatureof the articles is a function of the speed of the conveyor and quantityof liquid air used in the spray per unit time. J

The third form is similar to the second, ex-

cept that the articles are immersed in the liquid needed to freeze themand the quantity of liquid air used in the process.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illusthe best mode in which Ihave contemplated applying that principle. Other embodiments of theinvention embodying the same or equivalent principle may be usedandstructural changes may be made as desired by those skilled in the artwithout departing from the present invention and the purview of theappended claims.

In the drawings: Fig. 1 is a cross-section through a chamber in which'one form of this invention is utilized;

Fig, 2 is a cross-section through an apparatus utilizing another form ofthe invention; and

Fig. 3 is a cross-section through a chamber utilizing still another formof this invention.

Referring to Fig. l, the chamber I!) there shown is provided with a doorII in one wall thereof through which articles to be refrigerated arepassed. The articles are shown at |2 resting upon the floor |3 of thechamber and spaced from one another to permit circulation of therefrigerant around them. The articles may be mounted on stands (notshown), if desired, to permit circulation of the refrigerant around allsides thereof. Near the top H of the chamber and preferably at or near acorner is an insulated receptacle l5 lined with a suitable substance l6such as steelwhich will not deteriorate upon contact with a refrigerantat -300 F. Receptacle I5 is almost completely filled with liquid air |1through a pipe l8 passing through the top of the chamber. Pipe I8 isclosed by a cover |9 to retain all of the gaseous refrigerant within thereceptacle. The gaseous refrigerant occupies the space 20 and is emittedinto the chamber through a conduit 2|, a valve 22 and a suitable nozzle23.

The bottom of receptacle |5 has a pipe 24 leading therefrom to one ormore branches 25 from which the liquid air may be sprayed into thechamber either upon a tray 21 from which it evaporates into the chamberor directly into the chamber or onto articles placed therein.

In Fig. 2, the chamber is shown at 38 having openings 3| and 32 atopposite ends thereof. Within chamber 36 and extending substantiallyfrom one open end to the other is an endless belt conveyor comprising apair of drums 33 and which causes the upper or load side of conveyorbelt 31 to move to the left. Articles to be refrigerated such aspackages 42 are placed upon the conveyor belt 31 through opening 3| inchamber and are removed through opening 32. A platform 43 positionednear drum 34 receives the packages as they come off conveyor belt 31.

Directly below the load side of conveyor belt 31 is a receptacle 44 inwhich is stored a quantity of liquid air 45. A pipe 46 communicates withthe interior of receptacle 44 and conducts the liquid air to a pump 41,the outlets or high side of which is connected to a riser 48 whichempties into a tank 49 located above conveyor belt 31. The bottom oftank 49 is perforated or it may be provided with a plurality of nozzles50 which direct the liquid air upon the articles 42 as they pass throughthe chamber. A belt 5| and pulley 52 connected to pulley 39 of'motor 38supply the motive power for pump 41. The cold air resulting from thegasification of the liquid. air may 4 pass out of chamber 30 throughopening 3|, thereby serving to pre-cool the packages 42 before they aresprayed by the liquid air.

In the modification shown in Fig. 2Xthe rate of freezing is very rapidsince the ar icle to be frozen, viz. packages 42 come in direct contactwith the liquid air. The depth of freezingcan, of course, be regulatedby the speed with which the packages are passed through the chamber, andthis speed may even be such that the packages are merely cooled. Thusthe temperature of the packages as they leave the chamber may beregulated by regulating the speed of the con- It is understood, ofcourse, that suitable means is provided to render pump 41 a constantvolume pump, since the quantity of liquid air leaving tank 49 isconstant. It will be noted that the liquidair, after it leaves conveyor31 drains back into receptacle 44.

T-he modification shown in Fig. 3 differs from the modification shown inFig. 2 in that the packages are immersed in the liquid air instead ofbeing sprayed by it. Referring to Fig. 3, the refrigerating apparatus iscomprised of a chamber 55 having open ends 56 and 51. Adjacent open end51 is a well or tank 58 which is formed by building the floor of chamber55 at a lower level at end 51 than at end 56. Well 58 is filled withliquid air 59 which as it changes from liquid to gaseous state rises andflows toward end 56. The roof of chamber 55 ma be depressed at 66 toform a dividing wall and constrain a portion of the gasified refrigerantto travel in the direction of open end 56.

Two conveyors are used. The first operates entirely outside the liquidair well 58 and comprises an endless belt 6| passing over drums 62 and63 mounted on supports or stands 64 and 65, respectively, with a motor66 connected by a pulley 61 and belt 68 to a pulley 69 on drum 63 fordriving the conveyor .belt 6|. The direction of rotation of motor 66 issuch'that the load side of conveyor belt 6| is moved to the left asviewed in Fig. 3. Thus opening 56 constitutes the entrance or loadingend of the chamber. The articles 10 to be frozen are moved through-thecold air escaping from well 58 and are thus precooled. The articles dropinto the liquid air 59 when they leave conveyor 6|.

The second conveyor operates partly in the liquid air 59. It iscomprised of an endless belt 1| passing around a drum 12 mounted on astand 13 at the bottom of well 58, and around a drum 14 mounted on astand 15 angularly disposed with respect to the sides of well 58. Stand15 is located outside well 58 so that the end of belt 1| supportedthereby is likewise outside the well.

'A second drum 16 also mounted on stand 15 serves to raise the slackside of belt 1| over the edge of well 58. A motor 11 connected by apulley 18 and belt 19 to a driven pulley 86 on drum 14 supplies themotive power for belt 1 The direction of rotation of motor 11 is suchthat the drive side of conveyor belt 1| is moved to the left as viewedin Fig. 3, thus causing the articles which drop into the liquid air 58and upon conveyor belt 1| to be moved through open end 51 upon anunloading platform 8| exterior of the well. A guide plate 82 above drum12 constrains the articles to temperatures is available.

is theoretically twice the power required to produce a quantity of DryIce having the same heat abstracting capacity, the raw material forliquid air is free whereas the carbon dioxide used to form Dry Ice mustbe manufactured. The liquid air is easily handled and conveyed by tanksand pipes, whereas Dry Ice must be formed .into blocks, wrapped and thencarried to the place where it is to be used. It is well established thatthe most rapid heat transfer between substance existing in differentphases, e. g. liquid and gaseous phases, is between a surface and aboiling liquid, which situation obtains in the foregoing examples whenthe articles are immersed or in contact with the liquid refrigerant.

It is understood that the foregoing descriptio is merely illustrative ofthe preferred embodiments 'of this invention and .that the scope of thisinvention is not to be limited thereto but is to be determined by theappended claims. It is to be understood further that although liquid airis admirably suited to the refrigeratin methods disclosed herein, saidmethods are readily adaptable to other liquid refrigerants which possessthe physical property of liquifying at extremely low temperatures andpassing in a gaseous state while still at a low temperature.

Thus, while I have illustrated and described preferredembodiments of theinvention, it is to be understood that these are capable of variationand modification and I therefore do not wish to be limited to theprecise details set forth but desire to avail myself of such changes andalterations as fall within the purview of the following claims.

I claim: Y

1. The method of refrigerating an article which comprises providing arefrigerant which is adapted to pass from liquid to gaseous states, saidrefrigerant being provided in a chamber in both liquid and gaseousstates, prec'ooling the article with the gaseous refrigerant whilemoving the article through a portion of the chamber, then continuouslywetting the article with the liquid refrigerant during its movementthroughout the remaining portion of the chamher and regulating the finalaverage temperature of the article by the speed at which it is movedthrough the refrigerant.

2. The method of refrigerating an article which comprises providing arefrigerant which is adapted to pass from liquid to gaseous states, saidrefrigerant being provided in a chamber in both liquid and gaseousstates, precooling the article with the gaseous refrigerant while movingthe article through a portion ofthe chamber. flowing the liquidrefrigerant over the article during its movement throughout theremaining portion of the chamber and regulating the final averagetemperature of the article by the speed a at which it is moved throughthe refrigerant.

ROBERT H. HILL.

REFERENCES orrEn The following references are of record intbe file ofthis patent:

UNITED STATES PATENTS Diserens et a1. Feb. 2, 1948

